Variant Process Planning Systems for casting
Variant Process Planning (VPP) is, in essence, a storage and retrieval type of a system in which the data about some standard parts is stored. Given figure shows the steps in a typical VPP system.
Parts are grouped into families and a standard process plan is stored for each family. For the coding and classification of cast parts, multi digit schemes, similar to OPITZ, MICLASS or KK-3 codes used in machining domain have been used. [Wang and Li, 1991]. A typical multi digit coding scheme fore cast parts is depend on the attributes as under :
- Cast metal/Alloy grade
- Weight of part
- Batch size
- Part shape complexity
- Part Quality, Accuracy
- Production Equipment
- Casting Process
Coding systems with varying digits have been proposed to capture different scenarios. However the large variety of castings in terms of parameters related to shape, metal, process and quality and even larger variation in terms of their process plans is difficult to be represented by a limited digit code structure. More advanced techniques like Case Based Reasoning (CBR) are now being tried out to assess similarity between a new part and the standard parts in VPP systems.